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From |
"Seed, Paul" <paul.seed@kcl.ac.uk> |

To |
"statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu> |

Subject |
RE: st: data precision and problems therein |

Date |
Fri, 9 Nov 2012 14:12:42 +0000 |

Ngoc Minh PHAM points to a problem with non-integer cut-points. He can solve it with the -float()- function: Rather than gen gly_haem_gt_6_1 = gly_haem > 6.1 He can use gen gly_haem_gt_6_1 = gly_haem > float(6.1) Or (allowing for missing values ) gen gly_haem_gt_6_1 = gly_haem > float(6.1) if gly_haem <. Or (perhaps easier to remember): gen gly_haem_gt_6_1 = float(gly_haem) > float(6.1) if gly_haem <. This is because his variable is stored as a float (7 decimal places more-or-less), but 6.1 is evaluated exactly (or at least to double accuracy). Converting a float to exact is impossible (inventing extra decimal places); but going the other way is easy (just rounding). And float(float(x)) is the same as float(x), so extra float functions are not a problem. If Ngoc prefers to cut the other way... gen gly_haem_ge_6_1 = float(gly_haem) >= float(6.1) if gly_haem <. Paul T Seed, Senior Lecturer in Medical Statistics, Division of Women's Health, King's College London Women's Health Academic Centre, King's Health Partners (+44) (0) 20 7188 3642. > Date: Fri, 9 Nov 2012 15:28:08 +0900 > From: Pham Ngoc Minh <minh.pn@tnu.edu.vn> > Subject: st: data precision and problems therein > > Dear statalist, > > I have a problem with data precision as follows: > > for example: glycated hemoglobin is 6.1 (%) visible in data editor, > but it turns out 6.0999999 when clicked on, so are other numbers (5.6 > becomes 5.5999999), etc. This affects results of creating dummy > variables with pre-defined cut-points of values. How about the > solution? > > Thank you for your advice > > Ngoc Minh PHAM > National Center for Global Health and Medicine, Japan. > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/faqs/resources/statalist-faq/ > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/faqs/resources/statalist-faq/ * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: data precision and problems therein***From:*Pham Ngoc Minh <minh.pn@tnu.edu.vn>

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